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Showing posts from June, 2008

Highlights from the Blogosphere

"Alice and Bob"Backreaction A tongue-in-cheek quantum dialogue inspired by a Raymond Carver short story
"Colossal Construction: The World's Nine Largest Science Project" Discovery Channel Canada Seven of the nine are physics projects!
"The Real-Life Trash Robots Who Inspired Wall-E" io9 "For the past decade, a lot of our worst trash emergencies have been handled by robots...."
"The Guardian Science Course" Cosmic Variance Making science an integral part of culture
"Under the Same Sky" Built on Facts Mathematical musings inspired by Kate Chopin's novel, The Awakening

Tiny Telescopes

The year is 1908, the place is Tunguska, Russia, where a meteoroid or comet blasted into the earth's atmosphere and shattered to pieces, creating a 10-15 megaton explosion.

It downed 80 million trees over the Siberian forest, and scientists are certain that the sheer impact of the explosion would have destroyed any major world city.

In two years, we'll all be able to sleep a little easier at night, knowing that the earth's new watchdog, NEOSSat ( Near Earth Object Surveillance Satellite) is in orbit. Roughly the size of a suitcase, this tiny telescope will be perched 800 km above the earth.

Its sole job is detecting asteroids and other harmful objects before they collide with the earth. For 5 years it will snap photos of possible dangers and beam them back to earth, operating on less power than your average light bulb.

Developed by Canadian scientists, the solar-powered NEOSSat is capable of seeking out objects close to the sun. This is a huge advantage over ground based surv…

Whales versus Waves

Sound waves, that is. The Supreme Court recently decided to hear the U.S. Navy's appeal of a federal court ruling that banned sonar within 12 miles of the coast, and ordered the immediate termination of high-powered sonar when whales (and other marine animals) have been detected. In light of the sonar-whale dilemma, it might be helpful to run through the basics of underwater acoustics.

Sonar is the process of detecting what already happens to sound waves whenever there is a noise: an echo. As sound bounces off surrounding objects, some of them are reflected back to the noisemaker. The acoustic sound waves in sonar (an acronym for SOund Navigation And Ranging) are transmitted through the water in short pulses, where they travel at frequencies high above what humans can hear.

The reflected wave signals can then be detected and used to infer the distance and relative position of an object. The military uses sonar to detect enemy submarines and other tools of aquatic warfare. Keep in m…

Ptak Attack

Anyone ambling along the side streets of Georgetown in Washington, DC, between 1985 and 2002 might have had the pleasure of stumbling upon J.F. Ptak Science Books. It was a cozy, welcoming sort of independent bookstore, and the owner, John Ptak, took great pride in his specialty: "unusual, rare and unique material in the sciences and the history of science." Needless to say, much of that material dealt with the history of physics. It was a sad day for science buffs when the store closed its doors six years ago.
But now Ptak Science Books has risen like a phoenix from the ashes, finding renewed life online! That's right: John Ptak has gone digital. You can browse the Website at your leisure for books on every conceivable scientific subject, as well as antiquarian prints and maps from the 16th through 19th centuries. There's even a healthy stock of digital historical images available for downloading.
And the best part: John Ptak has a blog. His posts (he calls them &quo…

Mystery Crash Into Mars

Way back in 1984, when the Berlin Wall was still erect and everyone felt obliged to read George Orwell, a few astrogeologists came up with a theory to explain why the northern side of Mars is smooth and flat, while the southern side is marred with craters and highly elevated.

They proposed that something really large slammed into Mars, creating a creating split almost down the middle of the planet. Their ideawas influenced by another theory circulating at the time; that the moon formed by a chunk of Mars breaking off after a massive impact.

The major crash theory didn't develop much beyond that. After sitting on some dusty academic shelf for the past 25 years it has finally been revived, thanks to new evidence from recent research. Scientists now believe that something similar to an asteroid or a comet smacked into Mars about 4 billion years ago.

Moreover, the giant crater left over from the impact may be the largest in our solar system, about the size of Asia, Europe, and Australia …

Highlights from the Blogosphere

"Leaving Academia: Cry or Celebrate?"The Quantum Pontiff His Holiness ponders the implications of a colleague's decision to leave the Ivory Tower
"Universcale: Physics is All About Scales" Talk Like a Physicist An interactive online demo of scales from nanometers to nonillion-meters
"Homemade USB Fan" Sciencegeekgirl You know you've always wondered how to make your own USB fan; this video shows you how!
"Science, Criticism and fMRI" The Frontal Cortex What does fMRI really tell us about the inner workings of the human brain?
"Asteroid Apocalypse Prevention Finally Gets Some Funding" io9 Somebody page Bruce Willis and let him know the mission's back on!
"The X-Ray Photographer" Neurophilosophy Meet Nick Veasey, who is following in Roentgen's footsteps by taking photographic art into the X-ray regime.

The Planet Hunt

The search has begun for a planet just like earth-from lush green fields to mountains to cold deep rivers and waterfalls.

Of course, other earths would have to be made up of elements similar to our own, and orbit at a special distance required for liquid water to exist on its surface, called the habitable zone.

Astronomers are using new technology to scan other star systems for clues to unexplored earths. They are now capable of viewing faint wobbles in a star's motion, that are caused by the gravitational pull of an orbiting planet.

Advanced telescopes also let researchers watch for a dimming of light in stars that occurs as an orbiting planet passes in front of it. Thousands of stars can be monitored simultaneously.

In the winter of 2009 NASA will launch its Kepler mission, designed to seek out planets orbiting massive stars, like how our earth orbits the sun. Kepler will keep an eye out for starlight dimming in 100,000 stars.

It's a Bird, It's a Plane, It's...Glass?

Glass has always been a material shrouded in mystery. For decades it appeared to be structured in the same way as a liquid, or so scientists thought, in a form resembling both a liquid and a solid.

Recent research conducted in the UK has proved for the first time that glass is not structured as a liquid, but it's not a solid either. They discovered that glass forms 20-sided atomic structures called icosahedrons (see right), which form upon cooling.

This means that glass has some truly unusual properties that could one day lead to the development of airplanes made out of metallic glass. Metallic glass is a special type of shiny black material with plenty of useful applications, due to its strength, durability, and lightness.

Metallic glass is ideal for airplane wings in particular, because it does not form a crystalline lattice structure when cooled. In normal metals, stress between crystals can build up and cause fractures. In fact, this type of metal failure caused the world's…

Shortest Flash of Light Created

Scientists have created the shortest-ever flash of light, 80 attoseconds (one billionth of one billionth of a second) long. Up until now, the shortest light pulse is recorded at 130 attoseconds, set in 2007. These short flashes have huge implications; they might be able to let scientists view the movement of electrons around large atoms.

The flash was short enough to capture an image of a laser pulse previously too fast to be seen ( see photo on left). The method used to generate the flash is akin to a domino effect, initial pulses are fired into a cloud of neon gas, which in turn excite the neon atoms who release energy as super short flashes of light.

The flashes from the neon atoms were moved onto a second gas cloud so that the researchers could figure out exactly how short the light flashes were. Further analysis showed light flashing at 80 attoseconds. But scientists aren't done yet. The goal is to make light pulses as short as the time it takes for an electron to travel around…

Must Have Been Ice, But It's Over Now

NASA's Mars Phoenix Lander recently dug a trench on the Martian Landscape and captured photos of little chunks of white matter. Four days later, the mysterious stuff had disappeared. Scientists believe it was ice that went through the same process the snowman in your front yard does each winter; it evaporated.

Previously, there had been an ongoing debate as to whether or not the material was salt, but the disappearance confirmed that it must indeed be ice.

More ice surfaces are likely to be revealed as the robotic arm continues its work. Early on it refused to continue digging, even when it was told multiple times to explore a "polygon" region nearby the lander site. Halting is how the Phoenix is programmed to respond when it hits a hard surface beneath the soil.

Polygons are formed when permafrost (permanently frozen soil beneath the ground's surface) repeats a cycle of freezing and thawing, over many thousands of years. The result makes patterns comprised of cracks a…

Burnin' Wood Solar Style

Solar Dishes aren't normally used to burn wood, but that's exactly how MIT students recently tested their new type of solar energy collector. The wood promptly burst into flames and smoke.

The 12-foot wide dish is based on a design by inventor Doug Wood, who handed over the patent to MIT students, who then built a larger model using the same materials, aluminum tubing and strips of mirror.

The solar dish produces steam by concentrating sunlight up to a factor of 1,000. The mirrors that comprise the panel are cut into perfect parabolic shapes. Each parabola is pointed slightly differently, and is able to transform "pointed" light into strips.

Need a cup of steaming hot water? At the end of a 12-foot aluminum tube rising from the center of the dish is a coil of tubing that has water running through it. The cool water comes in through a hose, and is sent through a receiver tube and into a copper coil black-painted wire. The water is twirled around and around, letting all o…

Highlights from the Blogosphere

"Drunkard's Tennis and the Advice of Winners"The Quantum Pontiff
"Why Do Scientific Theories Work?" Evolving Thoughts
"Testing Your Free Energy Machine" Built on Facts
"MapQuest for Mars" Twisted Physics
"Spike Lee Will Uncover the Mysteries of Time Travel" io9
"Fermilab Takes Stage in The Da Vinci Code-like Thriller" Symmetry Breaking
And finally, courtesy of Asymptotia, check out the CDF Virtual Tour, where you can follow the path of a subatomic particle from its creation at the center of the detector all the way to the outer limits of the machine.

Magnifying Moon Tricks

While the moon is actually never full, this evening, Wednesday June 18th, it will seem abnormally huge to most people. Don't worry, it's only your mind playing tricks on you. This optical illusion, known as the Ponzo illusion, makes it seem as if the moon is bigger when it's near the horizon. The effect is exaggerated during the "full" moon.

Unfortunately, human eyesight can't be trusted when dealing with extremely large distances. The moon is not any larger overhead than it is near the horizon. Mario Ponzo first determined that our minds sometimes gauge the size of an object based on the background behind it. Because we perceive the sky as an extended dome, the moon appears to be very distant when on the horizon. On the other hand, things like clouds and airplanes, which are viewed directly overhead appear (and really are) much closer. So naturally. we tend to think that the moon is closer when viewed overhead too.

But the idea of the moon being farther away…

A Car That Wrinkles

The skin-like silver cloth stretched over BMW's new GINA Light Visionary Model (GINA stands for "Geometry and Functions IN 'N' Adaptions") is actually seamless fabric covered in a flexible wire mesh frame.

As a result, the car is capable of changing shape, bending and twisting like a living animal. The fabric is made of polyurethane-coated Lycra and is water resistant.

The aluminum frame is controlled by electric and hydraulic actuators, allowing the owner to alter the car's body shape at whim.

A whole host of questions about the design comes to mind. How is tension created to stabilize the fabric at high speeds?

Also, a car covered with a light fabric has much less mass that a gigantic SUV. The difference in force between the two cars upon impact at highway speed would be large enough to probably demolish the person in the GINA.

But I suppose the designers weren't too concerned about the consumer plausibility of it all (or people with scissors). This purely …

Cleaning Up Cosmic Dust

I imagine the earth must be fairly dusty by now, as it receives about 40,000 tons of dust particles from space each year. But once in awhile (NASA has been collecting dust since 1982), a unique mineral is found among the clouds of interplanetary dust.

Scientists recently discovered a new mineral, which is thought to have originated from a comet, although its properties are so unusual that no one is really sure where it comes from.

Space dust is particularly interesting because its composition holds clues as to how our solar system is formed. Very tiny clues. The grains of the mineral, a manganesesilicide named Brownleeite (named after astronomer Donald E. Brownlee) were approximately 1/10,000 of an inch in size. The researchers used a transmission electron microscope to study the mineral's nano-scale crystal structure and chemical composition.

Bending Starlight Solved by Non-Physicists

Two mathematicians fiddling around with an extension of the fundamental theorem of algebra had no idea of the significant implications their work held for gravitational lensing, a prediction of Einstein's general theory of relativity.

Turns out Dmitry Khavinson and Genevra Neumann proved physicist Sun Hong Rhie's theory on gravitational lensing. Gravitational lensing explains the deceptive behavior of light traveling at extremely far distances.

A gravitational lens forms when distant light from a particularly bright source, like a star, "bends" in both directions around a massive object. This cosmic optical illusion misleads the observer (usually here on earth), into thinking the light originates from 2 sources, when in fact there is only one. What looks like 2 different stars is actually the same star.

The light-tricks depend on where the massive object lies and how many massive objects there are. A star looks like a circle when the massive object is directly between t…

Not Your B-movie Flying Saucer

The skies could soon get a new addition: a plasma-fueled flying saucer. The mechanical and aerospace engineering professor who created the novel design calls its a "wingless electromagnetic air vehicle" (WEAV). The flat, circular spinning aircraft strongly resembles a flying saucer ( illustration of prototype on left).

WEAV has no moving parts, but power lies in its unique dynamics, the force generated by a current or magnetic field passing through a conducting fluid (known as magnetohydrodynamics).

Plasma (the conducting fluid) is generated by electrodes all over the surface of the aircraft that ionize the surrounding air. The generated plasma will coat the exterior of wave, producing stable lift and momentum. WEAV's design enables it to ascend into the air vertically.

It isn't all sunny days and clear coasting. Plasma driven aircrafts have always failed to fly on earth. The average plasma saucer has a much better chance in space, where there is less gravity and drag

Rad 1970's Space Colonies

I couldn't resist posting these artist's renditions of life in space, from a time when NASA was seriously contemplating space colonies.

Check out more space colony artwork from NASA here.

Cosmic Identity Crisis Resolved

Pluto, formerly known as the ninth planet in our solar system, has officially been given a new label: plutoid. The International Astronomical Union (IAU) decided on the name yesterday, which distinguishes all dwarf planets located farther from the sun than Neptune.

Dwarf planets are not-quite-planets, massive enough to assume a near spherical shape from self-gravitational force, but not large enough to have their own orbital zone, or become gravitationally dominant like real planets.

The discovery of Eris in 2003 triggered the reclassification craze. Eris, a dwarf planet larger and farther from the sun than pluto, is currently the only other plutoid aside from pluto.

Astronomers examining Eris' characteristics became aware of certain discrepancies in bodies characterized as planets. The demotion of pluto to a nameless dwarf planet by the IAU Committee on Small Body Nomenclature followed shortly in 2006.

Science for Sale

And by "sale" I mean anywhere between hundreds of thousands to millions of dollars. Titled "Important Scientific Books," from the library of retired physician Richard Green, next week in New York Christie's Auction House will be selling the original scientific works of folks like Descartes, Freud, Darwin, and Marx, to name a few.

I've been snooping around Christie's website and found several original edition books by noteworthy thinkers who laid the foundation for physics as we know it today. Or are at least responsible for all the units I had to learn in class. Here are some of the best (and most expensive):

Nicolaus Copernicus' 1543 "De revolutionibus orbium coelestium". This is where Copernicus notoriously described how the the sun, not the earth is at the center of the universe, and developed his ideas of planetary rotation around the sun.

Sir Isaac Newton's 1687 "Philosophiae Naturalis Principia Mathematica". It was here t…

Tangled up in Quantum

Scientists perform experiments in order to test a theory. If enough data is generated to support a claim, that claim is usually declared true. But what if the experiment continuously gave a predicted result only because the scientist was on earth? Perhaps a different outcome occurs in space.

This is the argument behind a recent proposal to launch a mission called Space-QUEST (Quantum Entanglement for Space Experiments). Anton Zeilinger of the University of Vienna submitted the proposal to the European Space Agency. He wants to perform quantum entanglement experiments for the first time in space, at the International Space Station (ISS).

Quantum entanglement describes the complex way particles are linked together, such that one cannot exist without the other, regardless of distance. Superposition, the ability to get two different but related measurements, is central to an understanding of quantum entanglement.

According to quantum theory, measurements made on linked particles, no matter h…

When Regular Atoms Become Superatoms

Atoms act really weird if only a few of them are grouped together. Gold and other (typically metal) atoms begin to form highly symmetrical structures depending on the number of atoms clustering together. These clusters take on the characteristics of the single atoms of a completely different element, transforming into what scientists have dubbed "superatoms".

What makes regular atoms become superatoms is their ability to transform physical properties and imitate those of other elements at extremely small scales. What we can observe with the naked eye, the size, shape and color of a certain material, changes as the number of atoms is reduced, starting at around a few million. For example, silicon is normally rigid and breakable, but group a small number of silicon atoms together and they become malleable, almost supple. Quantum dots, a type of semi-conducting particle, displays light across a spectrum of colors, depending on their size.

Superatom behavior is even more perplexin…

The Past, the Future, and Baby Universes

Thanks to fellow intern Justin Reeder for sending me an interesting article this morning, Does Time Run Backward in Other Universes?, published in Scientific American by cosmologist Sean M. Carroll.

The article (a formidable 6 pages) tackles those ever-so-elusive problems relating to the origins of our universe, and presents a couple of intriguing explanations. Almost as important are the comments at the bottom of the article, which provide a handful of concise critiques and different perspectives.

The author, a physics researcher at the California Institute of Technology, discusses the main ideas behind his and fellow colleague Jennifer Chen's theory that attempts to reconcile the arrow of time (the irreversible unidirectional time we observe) with certain characteristics of our universe, namely its entropy.

Carroll proposes that universes are created spontaneously by patches of ultra-dense dark energy, which expands rapidly into a vast empty space, before immediately shrinking and …

Does Physics Trump Ethics?

In what I think is a slightly Orwellian experiment, physicists from the Center for Complex Network Research at Northeastern University tracked the locations of 100,000 unknown people outside of the United States for 6 months, in order to determine their movement patterns. They found that about 70 percent of the time, people repetitively visited only 2 locations, which we can assume are work and home. In other words, most people don't get around much.The study was top-secret: performed in a mystery industrialized nation with a mystery wireless provider, and using mystery cell phones that had additional built-in tracking devices. Researchers used information from cell phone transmitter tower logs to analyze people's daily movements. Each tower has a specific zone, and is able to track all motility within that zone (usually about 2 square miles).
While the researchers didn't know the exact phone numbers, or precisely where the people were, studies performed without the con…

Physicist in Profile: Becky Thompson-Flagg

Imagine starting a new internship, first week on the job and you don't know a soul. But you're curious. How did these people get here? What are they like? Where do they come from? Do they have any cool body piercings?

Luckily,instead of spending months getting to know my co-worker Becky, I got to sit down with her and blatantly ask her lots of fun life questions. And she's got a cool tongue piercing.

Becky Thompson-Flagg's interest in science, like most things in her life, came about randomly. Sitting on the bus one day in high school, a classmate suggested that Becky would probably like the physics class she was taking, and that Becky should take it too. Not needing any further persuasion, Becky signed up and was hooked. Continuing on to Bryn Mawr College in PA, "I knew that I liked learning, and I knew that I liked science, but I didn't really know what to do about it," she says. Her quest for an intellectual challenge made physics an attractive option.

Bo…

Who Says Perfectionism is a Bad Quality?

Scientists have created the first metamaterial made solely of metallic elements, that is able to absorb all the light that hits it with perfection. Metamaterials are artificially constructed materials that have extraordinary properties and are revolutionizing physics, especially in the fields of optics and electromagnetism.

While natural materials use light in a limited number of ways, manmade metamaterials gain their unusual properties from their structure (rather than their composition) and can be developed to have properties beyond those of nature, allowing humans to control light in ways that were previously impossible. The metamaterial engineered by scientists from Duke University and Boston College has a particular geometric surface, which allows it to completely absorb microwaves.

Using computer simulations based on previous data, researchers created the metamaterial by designing resonators capable of individually joining to electric and magnetic components of an electromagnetic …

Magnetosphere Mondays

An exciting way to start off the week: Astrophysicists at NASA have recently discovered that energetic protons from the plasmasphere control pressure in the earth's magnetosphere. The term magnetosphere (aside from sounding sinister), is used to describe the surrounding region of planets dominated by a magnetic field, like Earth, Jupiter, Saturn, Uranus, and Neptune. The discovery challenges the way most scientists previously thought about the magnetosphere, as being most affected by solar wind.

They used a model to stimulate superstorm plasmas (the above picture shows what the Earth's magnetosphere looks like during a superstorm), which are often caused by sporadic ejections of solar material from the sun. These coronal mass ejections send billions of tons of plasma shooting out of the sun and hurling towards the earth at high speeds (millions of miles per hour).

Superstorm plasma isn't without its consequences on Earth, usually in the form of awesome visual displays like t…